Relationship between ventilation and predicted arterial CO2 pressure during recovery from an impulse-like exercise without metabolic acidosis.

We investigated ventilation ((V) over dotE) control factors during recovery from light impulse-like exercise (100 watts) with a duration of 20 s. Blood ions and gases were measured at rest and during recovery. (V) over dotE, end tidal CO2 pressure (PETCO2) and respiratory exchange ratio (RER) were measured continuously during rest, exercise and recovery periods. Arterial CO2 pressure (PaCO2 (pre)) was estimated from PETCO2 and tidal volume (V-T). RER at 20 s of exercise and until 50 s during recovery was significantly lower than RER at rest. Despite no change in arterialized blood pH level, PaCO2 (pre) was significantly higher in the last 10 s of exercise and until 70 s during recovery than the resting value. (V) over dotE increased during exercise and then decreased during recovery; however, it was elevated and was significantly higher than the resting value until 155 s (p<0.05). There was a significant relationship between (V) over dotE and PaCO2 (pre) during the first 70 s of recovery in each subject. The results suggest that PaCO2 drives (V) over dotE during the first 70 s of recovery after light impulse-like exercise. Elevated (V) over dotE in the interval from 70 s until 155 s during recovery might be due to neural factors.